Howdy - well begun is half done! (Although, seriously, these boats are a lot of work!)
There's a lot of info (including visual) in the AMP library:
http://amp.rokket.biz/lib_uboats.shtml, especially the Illustrated Guide to Uboat Research and Dougie's amazing The Wolf Pack. Those should pretty much get you everything you need to actually build a 1:1 boat. (Just add a few million 1930s dollars and some steel.)
Coat of Arms - well, for my money, if you're doing U352, then you're doing U352 the way she was. I'd go for it. At AMP, we reproduce the war flag/ Kriegsmarine flag with the Hakenkreuz, but do not do the Nazi Party flag. We offer a non historic alternative with an Iron Cross, which has the flavor without the symbol. You could so that on the coat of arms.
Perhaps it is the intention (history) behind what we build and display, but balanced with the end-effect. That said, what made you choose 352? There's the whole range of why here: some folks chose a boat because of the history, or a connection somehow to that boat, others because of "it's a good boat/cool accessories".
Keep pprogress pix!